Rock drill



No. 6l5,379. Patented-Dec. 6, I898. A; J. BANT.

' ROCK DRILL.

(Applica tlqn filed Jan. 21, 189B.)

2 Sheets-Shoat I.

(No Model.)

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2 Sheets-Sheet 2.

Patented Dec; 6; I898.

A. J. BANT.

ROCK DRILL.

(Application filed'J'an. 21, 1898.)

(No Model.)

THE NORRIS PETERS o0. PHOT6-LIY HO.. WASHXNGTGN. D, c:

UNITED STATES FATENT Genres.

ANTHONY JOHN BANT, or JOHANNESBURG, SOUTH AFRICAN REPUBLIC.

ROCK-DRILL.

SPECIFICATION formingpart of Letterslatent No. 615,379, dated December6, 1898.

Application filed January 21,1898- Serial No. 667,666- NO model-J To allwhom it may concern: 7

Be it known that I, ANTHONY JOHN BANT, residing at Johannesburg, SouthAfrican Republic, have invented Improvements in Rock- Drills, of whichthe following is a specification.

This invention relates to reciprocating rockdrills driven by steam orcompressed air; and it consists in improvements whereby the surfaces ofthe drill-piston operated upon by the motive power are duplicated inconjunction with a suitable valve and ports, giving reduction of weightcompared with other drills of the same power, economy of working, andgreater adaptability to various kinds of work, and, further, by aspecial spring reaction or compensation upon the feed-screw the slack orwear in the screw is always taken up, giving increased durability to thedrill as compared with others.

In order that this invention may be the better understood, I now proceedto describe the same with reference to the drawings hereto annexed andto the letters marked thereon.

Figure 1 is a longitudinal section through the drill and cradle. Fig. 2is an outside plan of the same with the valve-box removed. Fig. 3 is anend View of the same.

The drill-cylinder A is mounted so as to slide freely on ways in. thecradle B and is controlled as to its relative position to the cradle bythe feed-screw C and handle 0.

The compressed air or steam enters the. valve-box D by an inlet-port cland is admit,

ted to the required ports, as hereinafter more fully described, by thereciprocation of the piston-valve E, actuated by a rocking tappet e,which is moved at either end of the stroke by the shoulders f of arecess in the main piston F.

An interchangeable valve-face G is introduced between the valve-box Dand the cylinder A to facilitate renewal of the wearing parts.

The chief item of improvement in this drill lies in the arrangement ofduplicate pistonheads H and H, provided with spring packing-rings h tomake them steam or air tight, and in the arrangement of duplicate portsK k and L Z from each end of the valve-chest D, so that when the pistonvalve E is at one extremity of its stroke the ports K admit air or steamsimultaneously to the two faces 1) b of the duplicate piston-heads H H.The opposite faces of these heads a a are at the same time in communication,by the duplicate ports L Z, with the central exhaust port andexit M in the same position of the valve E. Upon reversal of the valve Ethe opposite effects of air or steam supply to the faces a a and exhaustfrom the faces b I) take place as regards the duplicate piston heads.This double action of piston is effected by the introduction of a fixedabutment or diaphragm N, provided with spring packing-rings n, and whichis conveniently and cheaply introduced and fixed into the plaincylinder-bore by a bush P, holding the said abutment against a shoulderin the bore.

The end of the piston-body F is bored to receive a rifled bar Q, whichworks in a rifled bush or nut q, screwed or otherwise fixed into thehead of the piston-body F.

On the end of the rifled bar Q is keyed a ratchet-wheel R,into the teethof which springpressed detents r engage. By this arrangement the inertiaand momentum of the pistonbody cause a partial rotation of the rifledbar at each stroke, causing a continued intermittent rotation of thepiston-head and drill at each double stroke.

The drill is fed forward by the feed-screw O, operated by the handle C.The feed-screw engages with a nut S, carried by a lug cast on the bottomof the cylinder A. The essential improvement upon this feeding device isthe introduction of a spiral spring T upon the feed-screw, reactingbetween the nut S and lug, and a nut V upon the feed-screw, thus takingup any slack or wear in the threads of the feed-screw and nut S.

The advantages gained by these improvements are great reduction inweight compared with other drills of the same power, economy of labor,greater adaptability for all kinds of work, and increase of durabilityby the compensating spring on the feed-screw, removing continuousvibrations which would otherwise arise from slack between the feedscrewand feed-nut.

Having now described my invention, what I claim, and desire to secure byLetters Pat= cut, is

1. ,In a rock-drill, the combination with a piston-rod, of two heads oneof Which has a long external recess, a fixed diaphragm through which therod passes at a point be tween the heads, a valve-chest having twosteam-ports each leading to similar sides of the same heads, and anexhaust-port always in communication with the external recess on one ofsaid heads, a cylinder having an cscape-port also in communication withsaid recess, a slide-valve controlling the steam and exhaust ports inthe steam-chest, and a rockarm engaging with the valve and projectinginto the said recess in the piston-head, sub stantially as described.

2. In a rock-drill in combination, a piston operating a drill havingduplicate steam or air tight heads an intermediate fixed diaphragm orabutment adapted to permit rod of said piston to WOl'k air-tighttherethrough a port from each end of both parts of the cylindercontaining the said piston-heads, duplicate ports from similar ends ofcylinder chambers uniting in a single port in steam-chest, a centralexhaust-port in steam-chest face, a D-valve over said ports insteam-chest, a rocking lever under said D-Valve to reciprocate same, andshoulders formed by a recess in one of said piston-heads to engage withand move said lever-head, substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing Witnesses.

AN'TIONY JOHN BANT.

Vitnesses:

Farmers Ennurn LANGLEY,

Jouinzxiis Arzmnns DANIEL Sunroxnur.

